type annotation vs working code

[Barry]

> On 1 Oct 2023, at 19:36, Richard Damon via Python-list <python-list at python.org> wrote:
> 
> Perhaps a better method would be rather than just using the name and catching the exception, use a real already_initialized flag (set to True when you initialize), and look it up with getattr() with a default value of False.
I would use a class variable not an instance variable.

class OnlyOne:
       sole_instance = None
       def __init__(self):
              assert OnlyOne.sole_instance is None
              OnlyOne.sole_instance = self

Barry